Perception of indoor environment quality in differently ventilated workplaces in tropical monsoon climates

Quarter of the global greenhouse gas emissions are related to generation of electricity by combustion of fossil fuel. Office buildings are one of the highest energy consumers of the built environment, employing over half of its end use energy for heating, ventilation, air conditioning and lighting. The intense solar radiation received in the equatorial regions requires that cooling and dehumidification provided inside buildings at all times to achieve comfort. Comfort is a strong indicator of workplace satisfaction which further influences productivity. The research investigates the perception of indoor environment quality (IEQ) in differently ventilated workspaces and the applicability of each ventilation type in the tropical monsoon climate. The surveyed utilized a seven point unipolar and bipolar scale to measure occupant's subjective evaluation of the indoor environment condition. Valid responses were collected from 523 participants of nine office buildings in Colombo, Sri Lanka. The buildings were categorized into three ventilation types for analysis: central air Conditioning (AC), ductless mini split system air conditioning (MM), naturally ventilated with operable windows and fans (NV). The perceived performance of AC and MM buildings were found to be similar in IEQ aspects; overall comfort, temperature comfort, temperature sensation, satisfaction with amount of natural light. AC and MM buildings were rated more satisfactory for overall comfort of indoor environment condition. The investigation reinforce the need for holistic, bottom up approach to design of environmentally sustainable office buildings.